Насчёт подарка я пока что не решила, что купить бабушке.

Насчёт means about, regarding, or as for.

So Насчёт подарка means about the gift or as for the gift.

In this sentence, it sets the topic:

• Насчёт подарка... = As for the gift...

It is very common in everyday speech.

Because насчёт requires the genitive case.

• подарок = nominative
• подарка = genitive

So:

• насчёт подарка = about the gift

This is something you just have to learn with the preposition:

• насчёт + genitive

For example:

• насчёт поездки = about the trip
• насчёт работы = about work

Пока что means for now, so far, or yet depending on the translation.

In this sentence:

• я пока что не решила = I haven’t decided yet / so far I haven’t decided

It adds the idea that the decision may still happen later.

Compare:

• Я не решила = I haven’t decided
• Я пока что не решила = I haven’t decided yet / for now I haven’t decided

Решила is past tense feminine singular.

Russian past tense agrees with the subject in gender and number:

• решил = masculine
• решила = feminine
• решило = neuter
• решили = plural

Since the speaker is я and is female, she says:

• я решила

A male speaker would say:

• Насчёт подарка я пока что не решил, что купить бабушке.

Because что купить бабушке is a subordinate clause.

The structure is:

• я не решила, что купить бабушке = I haven’t decided what to buy for grandma

Russian normally puts a comma before this kind of clause introduced by что.

Even though in English we often do not use a comma there, Russian does:

• Я знаю, что делать.
• Я не понимаю, что он сказал.
• Я решила, что купить. (less common by itself, but same structure)

It functions as the content of what has not been decided.

Literally, the sentence is something like:

• About the gift, I have not yet decided, what to buy for grandma.

More natural English:

• As for the gift, I haven’t decided yet what to buy for Grandma.

So что купить бабушке = what to buy for grandma.

It answers the hidden question:

• Не решила что? = Haven’t decided what?

Because бабушке is in the dative case, which is used for the person something is intended for.

• бабушка = nominative
• бабушке = dative

So:

• купить бабушке = to buy for grandma

Russian often uses the dative without a separate word for for in this kind of sentence.

Compare:

• Я купил маме цветы. = I bought flowers for Mom.
• Она готовит детям ужин. = She is making dinner for the children.

Because the direct object is represented by что.

• что купить бабушке = what to buy for grandma

The word что stands for the thing being bought.

If you named the object directly, you would say something like:

• Я решила купить бабушке шарф. = I decided to buy Grandma a scarf.

But here the speaker has not decided on the object yet, so что is used:

• I haven’t decided what to buy.

This is a matter of word order and emphasis.

Russian word order is flexible. Putting Насчёт подарка first makes it the topic:

• As for the gift...

It sounds natural if the speaker is moving to that subject specifically.

Compare:

• Насчёт подарка я пока что не решила, что купить бабушке.
  = As for the gift, I haven’t decided yet what to buy for Grandma.
• Я пока что не решила, что купить бабушке насчёт подарка.
  This sounds awkward and unnatural.

Starting with Насчёт подарка helps organize the sentence clearly.

Yes, it often could be omitted in Russian if the subject is clear from context.

For example:

• Насчёт подарка пока что не решила, что купить бабушке.

This still clearly implies I if the speaker is talking about themselves.

However, keeping я can make the sentence:

• clearer,
• slightly more explicit,
• or a bit more contrastive.

So both are possible, but я is perfectly natural here.

They are similar, but not always identical in tone or usage.

• о / об = about, concerning
• насчёт = about, regarding, as for

Насчёт often sounds a bit more conversational and topic-setting.

Compare:

• Я думаю о подарке. = I’m thinking about the gift.
• Насчёт подарка я ещё не решила. = As for the gift, I haven’t decided yet.

So in this sentence, насчёт works especially well because it introduces the topic: the gift.

Because the speaker is asking about what thing to buy, not choosing among already identified items by description.

• что купить = what to buy
• какой подарок купить = which gift to buy / what kind of gift to buy

So:

• что купить бабушке is broader and more natural here.
• какой подарок купить бабушке would be more specific: what kind of gift to buy for Grandma.

Both are possible in the right context, but they do not mean exactly the same thing.

Купить is perfective.

Here it is used in the infinitive after решить / не решить, because the speaker is thinking about a single completed action:

• what to buy

Russian commonly uses a perfective infinitive after verbs of deciding when the action is seen as a whole result:

• решил купить = decided to buy

The imperfective покупать would not fit well here:

• что покупать бабушке would suggest something more habitual or repeated, which is not the idea.

So купить is the natural choice for a one-time purchase.

Not very naturally.

A very literal version would be:

• About the gift I for now not decided what to buy grandma.

Natural English would be:

• As for the gift, I haven’t decided yet what to buy for Grandma.
• I still haven’t decided what to buy Grandma as a gift.

This is a good reminder that Russian and English often organize information differently, especially with topic phrases like Насчёт подарка.